Thanks a lot for the response! Looking back, maybe a shorter intro should have been used with, as you say, the drums kicking in earlier (and without the 2nd time repetition of the riff).
On the other suggestion, tthe part from 2:41 - 3:03 we just felt added some extra heaviness to the song. Although to be fair, the ascending/descending octave part from 3:03 - 3:25 is pretty lacking in ingenuity (but we all just loved playing that bit).
Many thanks, will keep you updated